Door stop mechanism



Oct. 29, 1968 E. PURKEY 3,407,535

DOOR STOP MECHANI SM Filed Aug. 5. 1966 TE 1. TE 2.

To Mater 15 To Motor I9 I INVENTOR. 20 EVERETT PURKEY Allonuy United States Patent 01 fice 3,407,535 Patented Oct. 29, 1968 3,407,535 DOOR STOP MECHANISM Everett Purkey, Crown Point, Ind., assignor to United States Steel Corporation, a corporation of Delaware Filed Aug. 3, 1966, Ser. No. 569,924 Claims. (Cl. 49-280) ABSTRACT OF THE DISCLOSURE A stop mechanism for preventing a lift-type door from closing accidentally. Includes a series of dogs pivoted to a vertical shaft mounted on the door frame. Normally the shaft is positioned to place the dogs in the path of stop carried by the lower corner of the door, whereby the dogs permit the door to open but prevent it from closing. T 0 permit the door to close, shaft turns 90 on a vertical axis and thus removes dogs from the path of the stop. Shaft is operated by same circuit as the motor which lowers door.

This invention relates to an improved stop mechanism for preventing a lift-type door from closing accidentally.

An object of the invention is to provide an improved stop mechanism which is of simple construction and does not interfere with intended opening or closing of a vertically movable door, yet effectively prevents accidental closing.

A further object is to provide a stop mechanism of the foregoing type which moves out of the way automatically when the door is closed intentionally and returns automatically to its effective position, and also can be operated manually when desired.

A further object is to provide a stop mechanism which can act to hold a lift-type door at any one of several heights.

The invention may be briefly summarized as including a series of dogs pivoted to a vertical shaft mounted on a door frame. Normally the shaft is positioned to place the dogs in the path of a stop carried by the lower corner of the door, whereby the dogs permit the door to open but prevent it from closing. To permit the door to close, the shaft turns 90 on a vertical axis and thus removes the dogs from the path of the stop. The shaft is operated by the same circuit as the motor which lowers the door.

In the drawings:

FIGURE 1 is an elevational view of a portion of a lift-type door equipped with my stop mechanism, taken from inside the door;

FIGURE 2 is an elevational view on a larger scale of the stop mechanism as seen from the right of FIG- URE 1;

FIGURE 3 is a horizontal section on the line IIIIH of FIGURE 1; and

FIGURE 4 is a horizontal section on line IVIV of FIGURE 1.

FIGURE 1 shows a portion of a lift-type door formed of upper and lower panels and 12 joined at 13 and slidable up and down in a frame 14. A reversible electric motor 15 is mounted on a base 16 fixed above the door for moving the door vertically to open and close it. A system of cables 17 and sheaves 18 operatively connects the motor with the door. The motor is controlled through a push-button switch which has up and down buttons 19 and 20. I have not shown these parts in detail, since they are conventional and subject to wide variation.

My improved stop mechanism comprises a vertical rod 21 journaled near its lower end in a thrust bearing 22 and received in a series of spaced pairs of aligned bearing blocks 23 fixed to the door frame 14. The rod carries a series of lugs 24, each located between a different pair of blocks 23. Dogs 25 are pivoted to the respective lugs on horizontal axes. The bottom corner of the lower door panel 12 carries a stop 26. As the door opens, this stop abuts the underside of each dog in succession. The dogs swing upwardly on contact, allowing the stop to pass. Each dog has a respetcive web 27 which normally abuts rod 21 and holds the dog in a position to prevent the stop from moving downwardly past the dog (FIGURE 3). The dogs gravitate back to thisposition after the stop passes as the door moves upwardly. I locate the dogs at various convenient heights to assure that the door does not drop accidentally below these heights. In the structure illustrated, the uppermost dog holds the door fully open, the next at a height to clear a tractor, and the lowermost at a height to clear a mans head.

When the down button 20 is pressed, rod 21 automatically turns 90 on its vertical axis to move the dogs out of the path of stop 26. The means for turning the rod includes a solenoid 28 mounted on the door frame 14 and a cooperating armature 29. The side face of the solenoid carries a depending bar 31 to which I pivot a bell crank 32. I pivot opposite ends of a link 33 to the armature 29 and to one arm of the bell crank. Rod 21 carries two laterally projecting levers 34 and 35. I pivot opposite ends of another link 36 to the other arm of the bell crank and to lever 34. The pivotal joints are sufficiently loose that the bell crank can move in an arc and the lever in a straight line through a limited distance. I connect the solenoid 28 with the down button 20 to energize the solenoid when this button is pressed; otherwise the solenoid remains de-energized. Energizing the solenoid raises its armature 29, which acts through the bell crank to turn the rod. A bar 37 is pivoted to the door frame 14 and extends through an opening in lever 35. A compression spring 38 encircles bar 37 and bears at its ends against lever 35 and a washer and nut 39 mounted on the bar. Thus the spring returns rod 21 to its operative position whenever the solenoid is de-energized. The lower end of rod 21 carries a crank 40 f0 turning the rod manually When desired.

I mount a limit switch 41 on the door frame 14 for actually energizing motor 15 in a direction to lower the door. Rod 21 carries an arm 42 which closes the limit switch after the rod turns about from its normal position (FIGURE 4). The limit switch opens when the rod returns to its operative position. Thus the motor can run in a direction to lower the door only when the rod is turned to a position in which the dogs 25 are out of the way of the stop 26.

From the foregoing description it is seen that my invention affords a simple stop mecahnism for positively holding a heavy vertically movable door from closing accidentally. The mechanism is entirely automatic in its operation and in no way interferes with normal opening and closing of the door.

While I have shown and described only a single embodiment of my invention, it is apparent that modifications may arise. Therefore, I do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

Iclaim:

1. The combination, with a lift-type door and a frame in which said door is mounted for movement upwardly and downwardly, of a stop mechanism for preventing accidental closing of the door, said mechanism comprising a member journaled on said frame to turn on a vertical axis, at least one dog pivoted to said member, a stop carried by said door, said member having an operative position in which said stop is engageable with said dog to hold the door against movement downwardly but in which said dog swings upwardly on contact with said stop as the door moves upwardly to allow said stop to pass, a solenoid and cooperating armature mounted on said frame, a linkage connecting said armature and said memher, said solenoid, armature and linkage turning said member on said axis when the door is closed intentionally to move said dog out of the path of said stop, and a spring operatively connected to said member for thereafter returning said member to its operative position.

2. A combination as defined in claim 1 further comprising a reversible electric motor operatively connected with said door for opening and closing it and switch means for controlling operation of said motor, said switch means being operatively connected with said solenoid to energize it before said motor is energized in a direction to close said door.

3. A combination as defined in claim 1 further comprising a reversible electric motor operatively connected with said door for opening and closing it, switch means for controlling operation of said motor, said switch means being operatively connected with said solenoid to ener- --gize it, and a. limit switch operatively-connected with said motor and actuated by said member to energize said motor in a direction to close the door when said member is turned from its operative position.

4. A combination as defined in claim 1 further comprising a crank connected to said member for turning it manually.

5. A combination as defined in claim 1 comprising a plurality of dogs pivoted to said member for engaging said stop when said door is at different heights.

References Cited UNITED STATES PATENTS 3/1916 Jones 292-44 X 8/ 1966 Tanaka 49-349 

